18 April 2011 last updated at 23: 01 GMT by Julian Miglierini BBC News, Mexico City

Acapulco, Mexico's prime tourist destination, takes a war much affected by drug-related violence, it is said, comes at a price – not only in human life, but also on the health of a country's economy.
Mexico, a bloody war against drug cartels, seems untouched by the conflict - but do business in that country is not easy for anyone in times of rising crime.
Mexico's economy is firmly - growing next 5.5% in the operations and optimistic expectations throughout this year, a healthy recovery from the effect on the neighbouring economy had recession in the United States.
Mexican Finance Minister Ernesto Cordero recently said there was "no evidence" the BBC suggest investors were from the conflict by the presence of organized crime groups by using the country as a route to transport dissolved drugs in the United States will be postponed.
As for tourism, one of the largest earners of Mexico's foreign currency, "we have very high rates of occupancy, it seems not affected," said Mr. Cordero, added, that the priorities for the violence were not usually tourists visited.
To say that on the Acapulco hotel.
Call a hit
The resort on the Pacific coast, one of the most important tourist destinations of the country for domestic and foreign tourists, has become a battlefield in the fight against organised crime.
Continue reading the most important story
everyone has problems, restaurants, bars, even people sell items on the beach "
end quote José Luis Espejel Copacabana hotel almost 700 people died in drug-related events since 2006 in the city, and shooting between rival drug cartels and with the security forces are common."
Foreign tourists have not targeted and district has hotel in particular through the violence - spared been but headlines around the world "Acapulco's descent into violence" reputation have badly tarnished the city.
Sitting under a sun lounger by the pool in the Hotel Copacabana, chief Concierge, José Luis Espejel admits that tourism is declining.
He talks about the "spring breakers", the U.S. University students, the from late February to early April South of the border for warm temperatures and beach parties herd.
Breakers was following warnings by some in the United States against travel to parts of Mexico, Acapulco from the radar for early in the year 2011.
Mr Espejel says, that during the last year about 2,600 students filled the rooms of the hotel, appeared in this year only 60. The official figures from the Acapulco authorities say the number spring break, which this year fell by up to 93% compared to 2010 came.
She had a huge impact on the town living.
"There are no jobs," he says.
"Low occupancy, no revenues, obviously no gains." "And these are not only hotels - everyone has problems, restaurants, bars, even people selling items on the beach."
Positive
Information according to the authorities visited some 22 million tourists Mexico in 2010, by 4.4% compared with 2009.

The Acapulco divers are one of the most important tourist attractions of the city
Critics say that the increase is nothing to celebrate - entry since the number of tourists was in 2009, as Mexico reported in the swine flu was the first country were had.
Other sectors of the economy are healthier indicators show.
The announcement, earlier this year, the US retail giant Wal-Mart, that it more than 1 billion $ invest would (£ 615 m) on the Mexican market was still further evidence of the Government, the foreign investors in the were put off by rising crime praised.
Antonio Ocaranza, spokesman for Wal-Mart Mexico, says that while she noticed some changes in the people's Party had purchase pattern - further grown, for example, in some areas of the country in which they avoided due to security concerns shopping after dark - their sales.
"We see that the current circumstances affecting some cities in the country, I, that this is a country, that think about what happens now, has tremendous growing opportunities."
In fact, Mexico rank high was the leading country in Latin America in a World Bank report on the ease of doing business - amount of hurdles a company credit or access to other criteria set - it.
Unemployment in Mexico is the lowest in all the Americas and one of the lowest between Member States of the Organization of cooperation and development (OECD).
' Extortion fee'
But it is argued that Mexico's economy good signs indicating the violence there could be prevented or more to grow.
Recently, a Chief Economist of BBVA, a number put on Spanish bank - one of the largest investors in Mexico.
"There would be no violence, the Mexican economy 1% on the prices of recent years would have grown", said Jorge Sicilia from BBVA analyst.
This is considered by many not only investment in additional security for companies, but attributed to the fact their business kidnapping and extortion turns have to drug cartels in sophisticated organized crime groups, spreading.
A survey of the American Chamber of Commerce in Mexico of more than 500 business, which leaders revealed that 67% felt less secure me do business in Mexico compared to the previous year.
The CANACINTRA national manufacturing industry Chamber recently estimated that in the year 2010 in the areas of violence had closed up to 10,000 small and medium-sized companies most concerned by the drugs.
Many of them had suffered extortion or threats of criminals, which called for the payment of a "fee" for their safety.
This is the case for a businesswoman in Central Mexico, preferred to remain anonymous.
She told the BBC that had six months ago, she and her husband, owners of a successful medium-sized enterprises, was approached by a group of armed men who identified themselves as members of la Familia drug gang.
She asked her, pay about $4000 (£ 2,465) each month - and to kill her and her family, if she are not threatened.
Fearing retribution from the criminal, when she alerted the authorities, they decided to pay.
"they appeared to collect the fee each month," visibly nervous says they, while walking to a park in Mexico City.
These episodes make many in Mexico fear like the drug war rages, other parts of the country could start lives the turmoil of that already faces Acapulco.